How about a tool that would generate a prototype disktab entry from
MODE SELECT data?
That *still* doesn't deal with the partition info, which is the
primary use of disktab to begin with. You can't divine that
information. (Hell; you don't even need a label if all you want to do
is access the raw disk.)
I, for one, have never used disktab under NetBSD. But that's another
subject.